It must be remembered though, that tumblers are polishers not cleaners - you will not get a shiny new looking part out if all that went in was a rusted, Coke stained bit of junk.
yeah, I know it cannot get rid of rust, but there is something on the parts that only seems to come off with days of tumbling
I dont want to use my buffing wheel on old stuff because I usually remove the last layer of Zinc plating